When a time report is run, if specific project names are selected in the Project filter, then the report would display only hours related to the specific projects only and no timeoff hours are shown. This happens even if Time Off Hrs, Time Off Type, or Time Off Description fields are selected in the column section.
This happens because the report displays the hours entered against the specific projects selected in the 'Project' filter. Since Timeoff's are not entered against any project, they would not be displayed.
In the Project filter select <None>, or
Disable Project filter.